Centering gauge for accurately locating a workpiece with respect to a keyway cutter or the like



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CENTERING GAUGE FOR ACCURATELY LOCATING A WORKPIECE WITH RESPECT TO AKEYWAY CUTTER 0R THE LIKE Filed July 5, 1947 IN VEN TOR. m

Patented Apr. 3, 1951 CENTERING GAUGE FOR ACCURATELY LOCATIN G AWORKPIECE WITH RE- SPECT TO A KEYWAY CUTTER OR THE LIKE Walter Blcsi,Dayton, Ohio, assignor to The Sheffield Corporation, Dayton, Ohio, acorporation of Ohio Application July 5, 1947, Serial No. 759,021

1 Claim.

This invention relates to centering gauges for accurately locating aworkpiece with respect to a keyway cutter or the like.

`One object of the invention is the provision of a gauge for relativelylocating the work axis with respect to the cutter of a machine tool, thegauge incorporating diverging arms that rest on the workpiece andpositioning means engageable with opposite sides of the cutter, withmeans for determining a predetermined relationship to a reference planeof the machine tool.

Another object is the provision of a centering gauge adapted forruse insetting up a machine tool such as a milling machine or the like so thatthe keyway cutter or other tool will be enabled to cut a keyway that istruly radial and permitting the proper positioning of the work and thecutter with respect to one another merely by adjusting the work or thecutter until the gauge assumes a predetermined position.

Another object is the provision of a centering gauge of the charactermentioned in which a positioning stop is adjustably mounted on a blockthat rests on the workpiece and cooperates with a locating iingermovably arranged on the block, the stop and nger being movable towardsand from a plane radial of the work and engageable with opposite sidesof the cutter to be used on the work.

Other objects and advantages of rthe invention will be apparent from thefollowingldescription, the appended claim, and the accompanying drawing,in which,

Fig. 1 is a front elevation of a gauge embodying the present invention,shown in its application to a machine tool;

Fig. 2 is a side elevation of the gauge shown showing its relation tothe workpiece and the cutter of a machine tool;

Fig. 3 is a top plan View of the gauge as it rests on the workpiece; and

Fig. 4 is a fragmentary sectional View of' a portion of the gauge bodyand illustrating the cutter engaging portions of the gauge.

Referring more particularly'tc the drawing, in which the same referencenumerals have been applied to like parts in the several views, lilgenerally designates a block of steel or other suitable material formingthe body portion ci a gauge that may be used for relatively positioningan annular workpiece H and a cutter I2 in setting up a machine tooladapted te perform a grooving or keyway cutting operation on the work.As shown, the cutter takes the form oi a rotatable milling tool arrangedon a shaft I3 forming part of the milling machine. The workpiece II isan annular workpiece located in the machine tool centers and suitablyheld against rotation. The machine tool table lli supports the workholding centers and may be raised or lowered and adjusted laterally inany desired manner `with respect to the cutter shaft I3, as is customaryin milling machines and the like, in order that the workpiece center maybe properly located below the center of the tool. In accordance with thepresent invention the workpiece center may be exactly located below thecenter of the tool so that the keyway cut into the workpiece by the toolwill be truly radial with respect to the workpiece without requiringintricate computations of workpiece size and extent of adjustments ofthe table I4.

The block I0 is provided with two downwardly diverging arms I6 and ilhaving suitable angular relationship such that these arms may rest onupper portions of the workpiece. Adjustably mounted in the block lo is alocating nger i8 adapted to contact one side of the cutter I2. Thisfinger is fixed tc a rod I9 secured by pin 29 to a control knob 2larranged if for sliding and rotational adjustment in a cylindricalpassage 22 in the block. A spring 23 arranged on the rod I9 yieldinglyurges the rod towards the right as viewed in Fig. 4, holding the iingerI8 in a normal position in which its cutter engaging face 2li lies in aplane designated by the line 25 which bisects the angle between thestraight Work engaging faces of armsV I 6 and Il. The lower portionk ofthe finger i8 is received in a groove or channel 26 when the linger isin its normal position but when the control knob 2| is pushed to theleft as viewed in Fig. 4 and turned, the linger I8 is pushed out of thechannel 26 and turned so as to lie at 90 degrees from its normalposition and contact with the surface 2l of the block, see Fig. 3. Thusit is displaced substantially from the plane 25.

Cooperating with the locating lnger'l is a positioning stop 28 shown inthe form of the adjustable anvil of a micrometer 29. This anvil is xedto the adjustment knob 3|! of the micrometer and the latter is fixed tothe barrel 3|, having graduations 32, cooperating with a xed index line33 on the stationary holder 34 in which the anvil is threaded. Theholder is secured in an upstanding projection 35 of the block Ill bymeans of a lock nut 36 engaging threads 31 on the holder. By turning theadjustment knob 30, the positioning stopv 28 is axially adjusted as inthe usual micrometer arrangement. The graduations 32 are such that azero indication is shown when the positioning stop engages the locatingfinger I8 at the plane 25.

Assume that the axial length of the cutter I2 is one-quarter of an inchfor cutting a one-quarter inch keyway in the workpiece. Under suchconditions the adjustment knob 39 would be turned to move thepositioning stop 28 one-eighth of an inch from its zero setting and thusone-eighth of an inch away from the plane 25 that bisects the anglebetween the diverging arms of the block. The locating finger I8 ispushed back and lowered to the position shown in Fig. 3. The work isthen adjusted upwardly by raising the table I4 and moved laterally untilthe positioning stop 28 contacts the side of the cutter I2. The controlknob 2| is then turned until the locating finger I8 is upright and thespring 23 thus yieldingly holds the locating finger against the otherside of the cutting tool.V The locating finger and the positioning stopare thus equidistant from the plane 25 and if the axis of the workpieceis exactly below the center of the cutting tool the plane 25 will betruly vertical so that when the gauge is removed the work can beadjusted upwardly and the groove or keyway cut in the workpiece will betruly radial. However, if the workpiece axis, as viewed in Fig. 1, is tothe right or to the left of the position shown, then the whole block Iwill be tilted out of its normal proper position. In order that theproper predetermined position of the block on the workpiece can bereadily determined with the geometric plane 25 exactly centered withrespect to the cutter, the blockk is provided with leveling means, shownin the form of a fiat finished reference surface 38 which has a knownangular relationship to the geometric plane 25. The reference surface38, as shown, is exactly 90 degrees from the plane 25 so that thereference surface should be exactly horizontal and parallel to thehorizontal plane I4 when the block is properly positioned and when thework is centered below the center of the cutter. This parallelrelationship of the surface 38 to the reference plane of the machinetool, namely the top of the table I4, may be determined by a surfacegauge shown at 39 having a movable feeler 49 that may be travelled alongthe surface 38 by sliding the standard 4I of the surface gauge along thetop of the table I4. If the same reading or indication obtains on thesurface gauge as the latter` is travelled along to the right as viewedin Fig. 1, in engagement with the reference surface 38, then theoperator knows that the plane 25 of the block is exactly vertical andthat the workpiece axis is exactly centered below the center of thecutter.

Thus the operator merely needs to know the size of the keyway to` becut, or in other words the axial length of the cutter, in order that hemay properly position the micrometer stop 28. The spring 23 positionsthe locating finger which is thus. held against the cutter andautomatically positions the gauge on the work. The operator by movingthe surface gauge 39 determines 6 Whether or not the surface 38 ishorizontal, and

if he finds that it is not he merely adjusts the workpiece axislaterally until it is. This makes unnecessary any of the laboriouscomputations of workpiece diameters, etc., and any exact measurements ofthe amount of travel of a workpiece from some reference point in orderthat the keyway cut in the workpiece may be truly radial in direction.

While the form of apparatus herein described constitutes a preferredembodiment of the invention, it is to be understood that the inventionis not limited to this precise form of apparatus, and that changes maybe made therein without departing from the scope of the invention whichis defined in the appended claim.

What is claimed is:

A centering gauge for centering the keyway cutter of a machine in aplane extending vertically upward from the axis of an annular workpiece,comprising a block having downwardly extending diverging arms free ofany connection at their terminal ends and for restingv on the workpiece,said block having a flat reference surface adapted to be brought into apredetermined exact relationship with a reference plane of the machinetool by relative axial adjustment of the cutter with respect to saidplane, a positioning stop adjustably mounted on said block for movementtowards a plane bisecting the angle between said arms, a micrometeradjustment for said stop and including means for indicating the positionof the stop with respect to said bisecting plane, a rod carried inr saidblock for rocking movement about its own axis and for axial movementtowards and from said; bisecting plane, a handle connected to one end ofsaid rod for rocking the rod and for moving the rod axially, a locatingfinger fixed to an end of said rod and operable into and out of aposition in which a portion of the finger is aligned with said stop,spring means operable to yieldingly hold the finger towards said stopand against the sides` of cutters of different widths to be used on theworkpiece for holding the cutter and the stop in yielding engagementwith one another irrespective of the position of adjustment within therange of adjustment of the stop on the block so that axial adjustment ofthe cutter causes the block to rock on the workpiece.

WALTER BLESI.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 455,644 Sloane July 7, 1891517,073 Sloane Mar. 27, 1894 1,486,667 Jerman Mar. 11, 1924 1,794,162Flamm Feb. 24, 1931 2,379,406 Alvis July 3, 1945 FOREIGN PATENTS 5Number Country Date 549,504 Great Britain Nov. 24, 1942

